Key mounting for musical instruments



g 1964 T. M. ANDERSON ETAL 3,145,510

KEY MOUNTING FOR MUSICAL INSTRUMENTS Filed Feb. 16, 1962 IN V EN TOR. THOMAS M. ANDERSON gg RON E. GOOD ATTORNEY United States Patent 3,145,610 KEY MQUNTING FOR MUSECAL INSTRUMENTS Thomas M. Anderson, 944 Highland Ave., Glen Ellyn, Ill., and Byron E. Good, 9158 W. Grand Ave., Franklin Park, Ill.

Filed Feb. 16, 1962, Ser. No. 173,685 14 Claims. (Cl. 84-380) This invention relates to musical instruments, especially wind instruments, and more particularly to an improved way of mounting an automatically, adjustably tensioning keys, valves and the like employed in wind instruments, such as clarinets, Saxophones, flutes, and oboes.

In the manufacture of wind instruments, it is customary to mount each of the keys or pads in a predetermined biased relation over a tone hole by means of a tensioning member or spring positioned at the fulcrum of the key or key carrier to thereby regulate the opening and closing of the tone hole. Of course, the tensioning member itself must be selectively locked to exert the desired amount of bias on the pad to hold it in normally closed relation over the tone hole. In our Patent No. 2,744,435, entitled Apparatus for Mounting Keys, Pads and the Like of Musical Instruments, there is described and claimed a novel and useful means for mounting and tensioning these keys or pads wherein the tensioning member or spring itself is disposed internally of the key shaft which is rockably positioned between the supporting ports for the keys; and, the present invention is directed to a greatly improved way of selectively locking a tensioning member in place, such as that described in our earlier patent, and in such a Way as to permit automatic, adjustable regulation of the tension applied by this member to the key or pad in holding it in biased relation against the tone hole.

In addition, the present invention is directed to an improved form of tensioning member which has particular application for use in the same manner as the member and apparatus set forth in our earlierpatent, and together with the novel and improved locking arrangement to be described provides for an effective and dependable way of positioning the keys or pads in place.

Accordingly, it is a principal object of the present in vention to provide for a novel and improved means for automatically and adjustably tensioning keys, pads and the like in biased relation to the tone holes in a musical instrument, especially wind instruments such as Clarinets, Saxophones and the like.

It is another object to provide for an improved construction and arrangement for mounting keys in desired relation to the tone holes in a wind instrument over that of the general type set forth in Patent No. 2,744,435 and in such a way that the locking and tensioning members are internally mountedand are cooperative to provide for more positive locking with adjustable automatic tensioning of the keys.

It is a further object of the present invention to provide a key mounting arrangement which is conformable for use with virtually all types and sizes of existing wind instruments and which accomplishes elimination of a number of parts normally employed in positioning the keys in desired relation, eliminates undesirable frictional contact between the moving parts, minimizes end and side play in the mounting arrangement, and in general establishes secure engagement between the moving parts.

It is a still further object to provide in a wind instrument a key mounting apparatus which enables regulation and locking of the tensioning member to apply the desired amount of bias to the key without necessity of I complicated adjustments or disassembly of any of the moving parts, and at the same time is of improved over- 3,145,610 Patented Aug. 25, 1964 all appearance and eliminates undesirable applications of stresses to the mounting elements and key itself.

It is an additional object of the present invention to provide in key mounting apparatus a novel and improved means for locking the tensioning member or padspring in place such that the tension applied by the spring may be easily and rapidly adjusted without the use of special tools or even partial disassembly of any of the elements forming the key mounting apparatus, and moreover wherein the locking means for the tensioning member is completely hidden, eliminates a number of parts, and may be easily assembled and disassembled.

The above and other objects of the present invention will become more apparent from the following detailed description taken together with the accompanying drawings in which:

FIGURE 1 is an elevational view, partly in section, illustrating a preferred embodiment of the present invention;

FIGURE 2 is a section view taken on lines 22 of FIGURE 1; and

FIGURE 3 is a cross-sectional view taken on line 3--3 of FIGURE 1.

For the purpose of illustration, the preferred embodiment of the present invention will be described in relation to the mounting of a hinge key which is customarily employed in a wind instrument such as a clarinet to control the opening and closing of the tone holes by the use of suitable pads, keys and the like. Although the principles of the present invention are by no means limited to this particular application, they are especially adaptable in the construction of a hinge key wherein essentially the key is lever-operated in hinged, biased relation about a key shaft which is conventionally mounted between a pair of supporting posts disposed in spaced relation to the tone hole and to one another; In order to bias the key in normally closed relation to the tone hole some tensioning means usually in the form of a spring is employed in association with the key shaft, and suitable means are also provided for locking the key shaft in position between the supporting posts with the tensioning means disposed to normally urge the key to the desired degree into closed relation over the tone hole. A preferred manner of applying the desired amount of tension to the key is set forth in our aforementioned patent in which a torque spring is extended longitudinally through the key shaft and by twisting the spring a selective degree, its tendency to unwind in the opposite direction will apply a corresponding force through the key shaft into the key to hold it in normally closed position. As pointed out, the advantages of such an arrangement are that the tensioning means is entirely concealed Within the key shaft and also by positioning the spring at the longitudinal axis or fulcrum of the key undesirable stresses are virtually eliminated along with any tendency for end or side play in the-connections between the key shaft and the post.

In accordance with the present invention the torque principle is preferably employed wherein the tensioning member in the form of a torque spring is locked in stationary relation at one end and at the opposite end is locked to the variable; that is, the key shaft which together with the key is adapted to rotate or swivel about a'stationary support. In order to disposethe torque spring in desired locked relation as described the present invention is directed first to the use of a clutch member especially adapted for positioning the variable end of the torque spring or member in locked relation to the key shaft and to the key itself and in a manner such that again the torque spring along with the clutch member is completely concealed; yet, these members may be selectively adjusted at any time to apply the desired amount of tent9 sion to the key without disassembly or loosening of any of the parts forming the mounting apparatus. It will be evidentfrom the following description that the specific form of improved torque spring along with the clutch member may be modified considerably in construction and relative disposition and accordingly that the present invention is not to be restricted in any sense to the specific arrangement to be described.

Referring particularly to the drawing, the preferred form of the present invention is shown in the mounting of the hinge key indicated generally at 13 which projects laterally from a main key shaft or tube 11 mounted between a pair of supporting posts 12 and 12' with a conventional lever and the like projecting laterally in an opposite direction from the key 13 whereupon pressing of the lever either by the finger or thumb will cause upward movement of the key and connected pad to open the tone hole on the instrument. In conventional practice, the key 13 and associated pad together with the key shaft 11 and lever 10 form an integral unit mounted in swivelled or rockable relation between the stationary supporting posts 12 and 12'. Essentially, in order to mount the shaft, key and lever in swivelled relation between the posts, tensioning means preferably in the form of a torque spring 14 extends longitudinally within the key shaft 11 and is locked at one end in stationary relation to the post 12' and at the opposite end is locked in a unique manner to the key shaft 11 by means of a clutch member preferably in the form of a coiled clutch spring 15.

To position both the torque spring 14 and clutch spring 15 within the key shaft 11 any suitable means may be provided and as illustrated the post 12 is bored part way through in coaxial alignment with the intended disposition of the key shaft to form an opening 18. Cornmunicating with the opening is a slotted portion 19, which is preferably vertically disposed, extending in coaxial alignment with the key shaft through the remaining portion of thepost from the end of the opening 18. This slot is sized to receive one end of the torque spring 14 and to hold it in stationary relation to the post thus to anchor it and permit twisting or turning movement of the opposite end of the torque spring relative to this stationary end to store up the desired amount of tension in the spring.

At the variable end of the torque spring 14 the post 12 is similarly bored to provide an opening 29 which is aligned with the axis of the key shaft for reception of an adjusting member which is preferably in the form of a slotted bolt 22. The latter includes a stem 23 dimensioned for extension in close fitting relation through the opening with a slotted portion 24 at its distal end to accommodate the variable end of the torque spring and a head 25 at'the opposite end of the stem which may be suitably formed, for example in the form of a hex, to permit rotatable adjustment of the bolt within the opening by a suitable tool such' as a wrench. V

The'torque spring 14 is disposed in locked but adjustable relation to the key shaft or tube 11 preferably by connection in press-fit relation of the stem 23 within an inner-concentric tubing 26. As shown, tubing 26 extends through the Outer key shaft 11 and at one end projects into the opening 18 formed in the post 12, and at the opposite end projects partway into the opening 20 formed in the post 12. The stem 23 may be permanently connected to the tubing 26 by any suitable means such as solder, although it is preferred merely to serrate or knurl the exterior surface of the stem 23 and to force it into the end of the tubing in secure, press-fit relation. In this manner, rotatable adjustment of the bolt head within the post 12 will also cause rotation of the inner tubing 26 together with turning of the torque spring 14. In addition, as will be noted, the inner tubing serves as a means of supporting the outer key shaft in journaled relation to' the posts while at the same time forming a means of connection in a manner to be described between the bolt and the clutch spring and in turn the key shaft itself. In practice, the inner tubing member 26 is thinwalled in relation to the outer key shaft 11, and may be composed of a suitable material such as stainless steel to provide the desired amount of support for the key shaft in relation to the posts 12 and 12'.

The primary feature of the present invention is the use of the clutch member 15 which as mentioned is preferably defined by a coiled spring which is positioned toward or at the variable or turning end of the torque spring 14. To mount the spring 15 in desired relation, the opening at the end of the key shaft adjacent to the post 12 is enlarged to form a spacing 30 between the exterior wall of the inner tubing 26 and the inner wall of the key shaft 11 for a limited distance and in addition an axial slot 32 is formed at the end of the shaft 11. The clutch spring 15 is coiled about the inner tubing 26 within the spacing 3t and the outer free end of the coil may be bent downwardly at right angles to the spring axis to form a hook 34 for projection through the slotted portion 32. In connected relation and upon disposition of the coiled clutch spring within the spacing St a limited space should exist between the inner wall of the key shaft 11 and the outer surface of the spring 15 so as to permit limited expansion of the coil spring which is important in accomplishing the clutching action necessary to provide for adjustable and automatic tensioning of the torque spring. To illustrate this clutching action it can be assumed from a direction facing the bolt head 25 that the coiled spring 15 is wound in a right hand, or clockwise manner about the inner tubing 26, as best seen from FIGURE 3, and it will be evident that a force ap plied to the hooked end 34 in a counter-clockwise direction will cause or urge the spring to contract about the inner tubing; whereas, a force applied in the opposite, clockwise direction will have a tendency to urge the coil spring to expand outwardly against the inner wall of the key shaft 11 and away from close engagement with the inner tubing 26.

Based on the realization that the clutch spring 15 may be caused to expand or contract depending upon the direction of movement of the outer key shaft 11 as force is applied to the hooked end 34, it will be observed that counter-clockwise movement of the key shaft, for example when the lever 1ft is pressed to open the tone hole, will cause the spring 15 and shaft 11 to move independently of the inner tubing 26 and the bolt 22 and torque spring 14-. On the other hand, when the key shaft is caused to rotate in a clockwise direction so as to cause the spring 15 to contract against the surface of the tubing 26, it has been found that the force of the spring in contraction is enough to securely and completely lock the shaft 11 and tubing 26 together so as to effectively lock the torque spring to the key shaft in this direction of movement.

Similarly, to bias the key 13 into closed position against a tone hole (not shown) beneath the key, the torque spring 14 can be adjusted in relation to the key shaft to apply the'desired amount of tension simply by rotating the bolt 22 counter-clockwise which will simultaneously urge the torque spring positioned in the groove 24 in a corresponding direction so as to load the spring or twist it with its urge to unwind in a clockwise direction. Here, simply by holding the key pad in closed relationto the tone hole the torque spring may be wound in the counterclockwise direction independently of movement of the key shaft 11. However, the tendency of the torque spring to unwind is immediately resisted by the coiled clutch spring which seizes the inner tubing 26 so as to lock it to the outer key tubing 11 thus thrusting the key itself into clockwise rotation and pressing its pad tightly against the tone hole. Accordingly, the inner tube 26 does rotate counter-clockwise independently of the key tubing 11 but immediately locks in the clockwise direction so as to urge the key into closed relation against the tone hole.

A number of substantial advantages are derived from this particular arrangement in that the torque and locking element for the torque spring are completely concealed and in the particular form described the clutch member 15 exerts very minimal friction when forced in the direction of expansion; whereas, a frictional engagement between the spring and tubing is great enough in the opposite direction to cause an immediate gripping action which is applied through the spring into the key shaft and key 13 to bias the key in desired relation. Accordingly, the arrangement completely eliminates the necessity for any exposed locking elements or set screws for example, and more important the thrust of the torque spring is applied uniformly through the clutch spring to the key shaft rather than by application at a concentrated point. Moreover, by concelaing the parts, periodic lubrication is unnecessary since the parts may be lubricated in the proper manner prior to assembly. Furthermore, by eliminating special locking elements on the exterior either of the key shaft or post, such as set screws, the main stress-bearing and force-applying members are not weakened in any Way and thus there is formed a more solid, rigid construction which will not have a tendency to loosen or require repairs under constant operation or play.

An additional feature of the present invention is the particular form of torque spring employed in conjunction with the clutch member to apply the desired amount of tension to the key. As Will be seen from the figures, the torque spring 14 is relatively long in relation to its width and of course dimensions of length and diameter of the torque spring will have a substantial effect upon the torque load which will be applied for a given amount of twisting or turning of the spring. Thus, for example, if the spring is lengthened or is of lesser diameter, then more rotation will be required to secure the proper tension; however, when a heavier spring or a spring of greater diameter is employed, although little turning is required, a fine degree of tension is more difficult to obtain. Accordingly the torque spring of the present invention has been devised to apply the proper amount of tension with minimum turning while at the same time enabling fine adjustment; This is accomplished preferably by employing a relatively thin wire such as piano wire and instead of the normal single length of wire, multiple lengths are employed which maybe formed by doubling or. tripling the wire or by forming a number of strands or leaves of the wire for extension through the inner tubing. Thus, a spring of this type provides a more delicate tension setting without sacrificing strength and further reduces build-up or sudden increase of load when the key is pressed into rotation. As illustrated, the torque spring 14 is in the form of a doubled spring which is actually the same as two separate springs but is more simply formed from a single wire for expediency and cost reduction. In addition, the double spring illustrated enables ease of assembly by secure placement of the closed U-shaped end 40 in the slotted portion 19, and free ends 42 may be bent for secure dis-' position in the slot 24 in the bolt 22. Moreover, the torque spring is preferably rectangular in cross-section so as to be easily bendable about its longitudinal axis but more rigid in the plane of its longitudinal axis so that any twisting movement applied by the torque spring will be applied almost completely about its longitudinal axis and directly through the key shaft to the key.

To assemble the mounting apparatus in position between the posts 12 and 12', and assuming that the openings 18 and 20 have been formed as described in the respective posts together with the slot 19, the clutch spring 15 is inserted into the space 36) with the free end or extension 34 secured in the slot 32 at the bottom of the key shaft. The 'keywshaft 11 with the inserted coil may then be placed between the posts, then the inner tubing 26 together with the slotted bolt 22 and the torque spring 14 is inserted or pushed through the opening 20 until the torque spring 14 projects into the slot 19 in the post 12 and the bolt is resting securely within the opening 20 in the post 12. Upon assembly, the torque spring 14 may be loaded under tension by rotation of the rivet until the proper bias is applied through the key to the key pad in relation to the tone hole. Under these conditions, the torque spring in being located at the fulcrum of the key and extending longitudinally within the inner tubing 26 applies a uniform loading through the key shaft and in this Way substantially eliminates lateral forces and uneven wear upon any of the parts forming the apparatus; also, the manner of formation and disposition of the clutch member cooperates in this regard to apply a uniform retraining action to the torque spring and to the entire assembly.

It will become apparent from the foregoing that a number of variations in the mounting apparatus of the present invention may be devised which are entirely within the principles thereof. As an example, however, the clutch member 15 may be formed in a number of ways to apply selective locking action between the variable end of the torque spring and the key shaft itself while remaining completely concelaed. More important, it is entirely possible to eliminate the intermediate or inner tubing 26 and resort to other means to selectively key the clutch member to the torque spring and also to interconnect the key shaft and post at the opposite end. Thus other connecting means may be employed between the post 12' and the key shaft and the clutch member may be mounted in direct connection with the torque spring such as by forming the clutch spring as a continuation of the end of the torque spring and coiling it directly about one end thereof for selective expansion and contraction in the same manner as in the preferred embodiment. Also,

the clutch spring as described may be employed as a locking means at both ends of the spring in much the same manner as shown at the single end. In addition, the clutch spring may be formed with a number of coil layers Wound upon one another in reverse directions for example for larger hinge key applications. In this connection, the size and dimensions of the wires and springs employed will vary depending upon the location of the hinge key. Thus for li ht keys; that is on keys falling under the weaker fingers, lighter wire may be employed as the torque spring, but those keys which fall under the stronger fingers require greater resistance and therefore heavier wire. In the latter instance, it is particularly desirable to use a double or multiple spring arrangement as the tensioning means.

The torque spring may be anchored to the post 12' in a number of ways other than through the particular form shown wherein the end of the post is slotted. For example, the opening 18 may extend completely through the post and an insert, formed in much the same manner as the stem 23, may be positioned to extend partially through the opening with a groove or slot at one end to receive the end of the torque spring to anchor it against rotation.

Although described with reference to a single hinge key it will be apparent that the principles of the present invention are readily adaptable for use with a series of keys, commonly referred to as a gang, wherein the intermediate post form common supports for oppositely extending key shafts for a series of tone holes, and in the relationship described and shown in Patent 2,744,435.

It is to be understood that While a number of modifications have been suggested, a number of additional modifications and changes in the construction and arrangement of our improved key mounting may be adopted; also the composition of materials employed may be varied, without departing from the scope or principies of the present invention as defined by the appended claims and equivalents thereof.

What is claimed is:

1. In a musical instrument wherein there is provided at least one tone hole together with a pair of stationary supports disposed in spaced relation and being adapted for mounting of a key member in hinged relation to the tone hole, the combination of means for mounting the key in hinged relation to each tone hole comprising, inner and outer concentric members with the key being connected to the outer member, a tensioning member within the inner member being connected at one end to one of the supports and at the other end to said inner member, and clutch means interposed between said inner and outer members to provide for rotation of said outer member independently of said inner member in one direction and to key said inner and outer members together for rotation in the opposite direction whereupon the key is selectively biased in normally closed relation with the tone hole.

2. In a musical instrument wherein there is provided at least one tone hole together with a pair of stationary supports disposed in spaced relation for mounting of a key in hinged relation to the tone hole, the combination of means for mounting the key in hinged relation to each tone hole comprising, inner and outer concentric, gen erally tubular members with the key being connected to the outer member, resilient tensioning means within the inner concentric member being connected at one end to one of the supports and at the other end to said inner concentric member, and a clutch member interposed between said inner and outer members in connected relation to one end of said outer concentric member, said clutch means being operative to provide for rotation of said outer member independently of said inner member in one direction and to key said inner and outer members together for rotation in the opposite direction whereupon the key is selectively biased in normally closed relation with the tone hole.

3. In a musical instrument according to claim 3 wherein said clutch member is defined by a coiled spring capable of expanding upon rotation of the key in one direction, and of contracting upon rotation of the key in the opposite direction.

4. In a musical instrument wherein there is provided at least one tone hole together with a pair of stationary supports disposed in spaced relation to permit mounting of a key in hinged relation to the tone hole, the combination of means for mounting the key in hinged relation to each tone hole comprising, inner and outer concentric, generally tubular members with the key being con nected to the outer member, a tensioning member within the inner concentric member being connected at one end to one of the supports and at the other end to said inner concentric member, a clutch interposed between said inner and outer members at the end adjacent said other end of the resilient means being operative to provide for rotation of said outer member independently of said inner member in one direction and to key said inner and outer members together for rotationin the opposite direction, and means connected to said tensioning member to selectively tension said member for biasing the key in closed relation to the tone hole.

5. In apparatus for mounting each of a series of keys on a musical instrument in hinged, biased relation to each of a corresponding series of tone holes wherein there is provided a key shaft disposed in journaled rela tion between a pair of stationary supports along with a tensioning member disposed within the shaft being fixed at one end to a support, a clutch member interposed be tween the other end of the tensioning member and the interior of the shaft being operative to key the shaft and tensioning member together for rotation in one di rection while the shaft and tensioning member are free to rotate independently of one another in the opposite direction.

6. In apparatus according to claim .5 wherein said clutch member is characterized by a coiled spring wound in a predetermined direction with one end being fixedly connected to the shaft.

7. In a musical instrument having at least one tone hole together with stationary support members arranged in spaced relation to one another and to the tone hole, the combination therewith .of an apparatus for mounting a key and the like in hinged, normally closed relation to each tone hole comprising an outer, generally tubular member including means for supporting said tubular member in journaled relation between said stationary supports, a tensioning member within the outer tubular member being connected in stationary relation at one end to one of the supports, and a clutch member interposed between the other end of said tensioning member and the interior wall of said tubular member, said clutch member being operative to provide for independent rotation of said outer tubular member in relation to said tensioning member in one direction and to lock said outer tubular member and said tensioning member together for rotation in the opposite direction.

8. In a musical instrument according to claim 7 wherein said tensioning member is defined by an elongate, doubled wire having its closed end anchored to the support.

9. In a musical instrument having at least one tone hole together with stationary support members arranged in spaced relation to one another and to the tone hole, the combination therewith of an apparatus for mounting a key and the like in hinged, normally closed relation to each tone hole comprising an outer, generally tubular member including means for supporting said tubular member in journaled relation between said stationary supports, a tensioning member within the outer tubular member being connected in stationary relation at one end to one of the supports, a clutch member interposed between the other end of said tensioning member and the interior wall of said tubular member, said clutch member being operative to provide for independent rotation of said outer tubular member in relation to said tensioning member in one direction and to lock said outer tubular member and said tensioning member together for rotation in the opposite direction, and adjusting means associated with said other endvof said tensioning member to provide for selective tensioning of said member so as to bias it for movement in. locked relation with said outer tubular member.

10. In a woodwind instrument having a series of tone holes together with a pair of stationary posts for each tone hole spaced in relation to the tone hole and to one another, the combination of a hinge key assembly extending between each pair of posts comprising, an outer tubing having a key extending laterally for disposition over the tone hole and a lever for said key, an inner tubing disposed in spaced concentric relation with said outer tubing, a torque spring extending longitudinally through said inner tubing being adapted to be twisted about its longitudinal axis, a connector in one post to lock said spring at one end to the post, tension adjusting means for twisting said spring being journaled in the other post in locked engagement with said inner tubing and said spring, and a clutch spring coiled about said inner tubing having one end thereof connected for movement with said outer tubing and being coiled in a direction such that said outer tubing is rotatable independently of said inner tubing in moving the key away from the tone hole and is rotatable in locked relation with said inner tubing in a direction moving the key toward the tone hole.

11. In a woodwind instrument having a series of tone holes together with a pair of stationary posts for each, 7

tone hole spaced in relation to the tone hole and to one another, the combination of a hinge key assembly extending between each pair of posts comprising,,an outer tubing having akey' extending laterally for disposition over the tone hole and alever for said key, an inner tubing disposed in spaced concentric relation with said outer tubing and with the spacing between said tubing being enlarged at one end thereof, a torque spring extending longitudinally through said inner tubing being adapted to be twisted about its longitudinal axis, a connector in one post to lock said torque spring at one end to the post, tension adjusting means for twisting said spring being journaled in the other post in locking relation to said inner tubing and said spring, and a clutch spring coiled in the enlarged space about said inner tubing having one end thereof connected for movement with said outer tubing and being coiled in a direction such that said outer tubing is rotatable independently of said inner tubing in moving the key away from the tone hole and is rotatable in locked relation with said inner tubing in a direction moving the key toward the tone hole.

12. In a musical instrument wherein there is provided at least one tone hole together with a pair of stationary supports disposed in spaced relation and being adapted for mounting of a key member in hinged relation to the tone hole, the combination of means for mounting the key in hinged relation to the tone hole, the combination of means for mounting the key in hinged relation to each tone hole comprising, inner and outer concentric members with the key being connected to the outer member, a tensioning member within the inner member being connected at one end to one of the supports and at the other end to said inner member, and a coiled spring associated with said inner and outer members to provide for spring biasing said key to a closed position when said key is moved to the open position.

13. In a musical instrument having at least one tone hole, a key cooperating therewith and a lever for operating the key; means for supporting said key spring biased into closing position with said tone hole, comprising: a first and second support member mounted on said instrument; said first support member having a first bore therethrough of substantially uniform diameter and said second support member having a second bore therein extending only partially therethrough and a counterbore of reduced diameter; an outer cylindrical shaft rotatably mounted between said supports having an enlarged internal diameter area at one end and supporting a key and a lever on opposite sides thereof; an inner cylindrical shaft mounted concentrically of said outer shaft and journaled in said first and second bores; a tensioning bolt in said bore having a recess in its internal end; a tensioning rod in said internal shaft having its ends fixedly attached in said counterbore and recess, respectively, and a coiled spring in said enlarged diameter area between said shafts and having one end attached to said outer shaft so that said outer shaft will move in one direction independently of said inner shaft and said shafts will be locked together by said spring for movement together in the other direction.

14. The device of claim 13 in which the tensioning rod is a continuous U-shaped member with the bend portion inserted in said second bore.

References Cited in the file of this patent UNITED STATES PATENTS 2,744,435 Anderson et a1. May 8, 1956 2,895,578 Winchell July 21, 1959 FOREIGN PATENTS 172,103 Switzerland Feb. 16, 1935 

1. IN A MUSICAL INSTRUMENT WHEREIN THERE IS PROVIDED AT LEAST ONE TONE HOLE TOGETHER WITH A PAIR OF STATIONARY SUPPORTS DISPOSED IN SPACED RELATION AND BEING ADAPTED FOR MOUNTING OF A KEY MEMBER IN HINGED RELATION TO THE TONE HOLE, THE COMBINATION OF MEANS FOR MOUNTING THE KEY IN HINGED RELATION TO EACH TONE HOLE COMPRISING, INNER AND OUTER CONCENTRIC MEMBERS WITH THE KEY BEING CONNECTED TO THE OUTER MEMBER, A TENSIONING MEMBER WITHIN THE INNER MEMBER BEING CONNECTED AT ONE END TO ONE OF THE SUPPORTS AND AT THE OTHER END TO SAID INNER MEMBER, AND CLUTCH MEANS INTERPOSED BETWEEN SAID INNER 